Research Article

Durability Modeling of Environmental Barrier Coating (EBC) Using Finite Element Based Progressive Failure Analysis

Table 3

Failure criteria used in life prediction of composite specimens.

Mode numberFiber failure criteriaEvent description

1Longitudinal tensile ( )Failure of ply controlled by fiber tensile strength and fiber volume ratio

2Longitudinal compressive ( )(1) Fiber/matrix delamination under compression loading
(2) Fiber microbuckling
(3) Fiber crushing

3Transverse tensileMatrix cracking under tensile loading, event controlled by matrix tensile strength, matrix modulus, and fiber volume ratio
Transverse compressiveMatrix cracking under compressive loading, event controlled by matrix compressive strength, matrix modulus, and fiber volume ratio
Normal tensile ( )Plies are separating due to normal tension

4Normal compressive ( )Due to very high surface pressure that is crushing of laminate

5In-plane shear ( )Failure in-plane shear relative to laminate

6Transverse normal shear ( )Shear failure acting on transverse cross-oriented in a normal direction of the ply

7Longitudinal normal shear ( )Shear failure on longitudinal cross section that is oriented in a normal direction of ply
Normal tensile ( )Combined stress failure criteria used for isotropic materials
Relative rotation criterion (RROT)Considers failure if the adjacent plies rotate excessively with one another

8Transverse normal shear ( )Considers invariant through-the-thickness

9Linear elastic fractureVirtual crack closure technique (VCCT), discrete cohesive zone model (DCZM)